Compositional evolution of Bi-induced acceptor states in GaAs1-xBix alloy

Far-infrared absorption measurements have been performed in nominally undoped GaAs1-xBix (0.6% <= x <= 10.6%) for magnetic field up to 30 T. For 0.6% <= x <= 4.5%, the Lyman series of an acceptor has been observed. An exceedingly high value of the ground-state g factor provides strong evidence of Bi-related acceptor states. For x >= 5.6%, however, these acceptors suddenly disappear. Such anomalous dependence on Bi concentration parallels those recently reported in GaAs1-xBix for other electronic and structural properties.